1991 Mariah PCM 351 stalls after a few seconds

[joe Schnur]

Well carb rebuilt still no joy

[chris young]

Curious, if the carb is rebuilt and you're sure you're getting fuel, my next suspect would be a vacuum leak. Your PCV could be stuck open. I'd pull the hose off the carb and plug the inlet. How did the problem manifest? Was the boat running fine and now it's not? Will it run if you leave it in neutral and keep the thottle up? I think someone else had a very similar problem and it turned out to be a collapsing fuel hose. I'd suggest running a brand new hose from the fuel pump into a gas can and that eliminates that possibility. How long does it run before it dies? It should run about 15 seconds on the fuel bowl. If you've got a really restricted fuel flow for whatever reason, I would suspect that after it dies, you would have to crank it for several seconds before it will start again. An easy way to check that is to take the flame arrestor off, run it until it dies and then check to see if the accelerator pump is still pumping fuel without re cranking. If so, I'd say it's not a fuel starvation issue.

[joe Schnur]

Thanks Chris new hose in place 6 to 10 secs idled to the end of lake after a weekend of skiing pulling a barge. On drive back to the dock it just would not stay running and killed the batt trying to start tried a spare batt no joy .

[joe Schnur]

Thinking about coil just frustrating in garage now. Will take to shop in march if I get no new ideas

[chris young]

So this seems to be a random issue? The only other thing I can think of would be your electric choke is not working correctly.

The boat would start normally cold, but once the engine was warm it would be very hard if not impossible to start, and wouldn't want to keep running at low RPM. While you're skiing it would run pretty well off the secondaries, just rich but still lots of power. This one is pretty easy to test, just turn the key on and leave it on for a while and check to see the choke opens and stays open. I'd leave it that way for a couple of hours and check it every 10 or 15 minutes.

Good luck

[joe Schnur]

Rebuilt carb had to adjust the idle screw way down the engine was pulling gas through and flooding also had to replace the floats with brass ones